FIG. 8 shows a drawing disclosed in Japanese Patent Application Laid-open No. 5-257529.
As shown in this figure, an unmanned dump truck 20, which is a moving body, is guided along a scheduled course 50 with a known dead reckoning method.
Should the dump truck 20 then move to a prescribed standby point, this standby point is designated the starting point; an operator of a loader 60 at a loading point PL on a working face uses a radio controller to remotely operate and cause the dump truck 20 to approach the loading point PL of the loader 60. On the basis of the position and direction data of the loading point PL which was actually arrived at through such remote operation, this dump truck 20 generates a branch course CL, SL and sends the position data of this branch course to other dump trucks.
In this case, the transmission and reception of the branch course position data is effected among a plurality of dump trucks moving through a large work site.
As a result, each dump truck can be guided with the dead reckoning method on the branch course.
The conventional method for generating branch courses is generally effected with the following procedures.
Specifically,
(a) A straight circuit course 51 which is roughly parallel to a working face is established in advance.
(b) A dump truck 20 is guided from a prescribed standby point to a loading point PL through radio controlled guidance; its position coordinates and azimuth are calculated and stored.
(c) The crossing point PC of an extension line 54' in the direction of the azimuth at the loading point PL with the circuit course 51 is calculated.
(d) The crossing angle .phi. of the extension line 54' and the circuit course (straight line) 51 at the crossing point PC is found. This crossing angle .phi. is limited to 45.degree..ltoreq..phi..ltoreq.135.degree.. When this crossing angle .phi. falls outside this range, the branch course is not generated.
(e) The turning radius r in accord with the crossing angle .phi. is determined.
(f) The point PS at which the arc CL with radius r inscribed in the two straight lines 51 and 54' is tangent to the circuit course 51 is found and designated as the stopping point. Thereby a branch course comprising the arc CL and the straight line LS is generated.
When a branch course is generated in this way, a dump truck 20, which moved from a scheduled course 50 on a circuit course 51 as shown by the arrow, stops at the stopping point PS and is guided by dead reckoning to back up to a loading point PL along a branch course comprising an arc CL and a straight line SL.
However such a method for generating a branch course presupposes that, as shown in (a) above, the working face is in a straight line and has a certain length and accordingly the circuit course 51 also is parallel to this working face and is a straight line of a certain length.
In effect, the generation of a branch course is limited by the form of the working face and the form of the scheduled course.
Also, as shown in (d) above, the crossing angle .phi. of the straight circuit course 51 and the extension line 54' is limited to 45.degree..ltoreq..phi..ltoreq.135.degree.. Therefore a branch course cannot even be generated if these line segments do not cross to begin with.
In effect, the generation of a branch course is limited by the azimuth of the dump truck 20 at the loading point PL.
Also, as shown in (f) above, it is presupposed that the stopping point PS can be established on the circuit course 51. A branch course cannot be generated when the stopping point PS cannot be established on the circuit course 51.
In effect, the generation of a branch course is limited by the azimuth and coordinate position of the loading point PL.
Before now, as noted above, the generation of a branch course was limited by the form of the working face, the form of the scheduled course, and the azimuth and coordinate position of the loading point PL and it could not be certain that a branch course would be generated.
With the foregoing facts in view, it is a first object of the present invention to provide a course generator of moving body which can for certain generate a branch course, regardless of the form of a working face, the form of a scheduled course, and the azimuth and coordinate position of a loading point PL.
As discussed above, the transmission and reception of the branch course position data is effected among a plurality of dump trucks which are moving through a large work site.
However, when an arrangement is made in such a manner, the dump truck which generated the branch course must transmit a large amount of data individually to many other dump trucks. For this reason, the working efficiency of the dump truck is decreased by the amount of time necessary for transmission processing.
Also, in the case where communication is performed randomly among dump trucks, the frequency bands of the dump trucks' transmitter/receivers must be separated in order to avoid cross talk of the communications. This increases costs of communications devices and the complexity of the operations.
Also, since transmission and reception are effected in a large work site, the communications power must be at certain level or higher on the assumption that the dump trucks are far apart. This causes difficulties legally and in terms of costs.
With the foregoing facts in view, it is a second object of the present invention to provide a course generator of moving body which can resolve the difficulties discussed above, such as poor working efficiency resulting in the case where communication is performed randomly among moving bodies.